Process of producing nitrogen compounds.



O. E. ACKBR. PROCESS OF PRODUCING NITROGEN COMPOUNDS. APPLICATION rum) MAR.'23,1909.

1,051,303, Patented Jan. 21, 1913.

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Inveniaf:

O. E. ACKER. PROCESS OF PRODUCING NITROGEN COMPOUNDS. APPLIGATION FILED 1l1Ui.23,1909v 1,051,303. Patented Jan.21, 1913.

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UNITED STATES PATENT orrron.

CHARLES E. ACKER, OF NEW YORK, N. Y., ASIGNOR TO THE NITROGEN. COMPANY, A CORPORATION OF NEW YORK.

PROCESS OF PRODUCING NITROGEN COMPOUNDS.

Specification of Letters Patent.

Patented Jan. 21, 1913.

Application filed March 28, 1909. Serial No. 485,344.

ducing Nitrogen Compounds, of which the following is a specification.

In my U. S. Letters Patent Nos. 914,214 and 914,100, dated March 2, 1909. I have described'methods ot fixing nitrogen and producing: nitrogen compounds, such as nitride, amids, cyanamids and cyanids, involving the electrolysis of a fused salt or compound, 0, 1., sodium chlorid, in contact with a molten metallic cathode, c. 9., lead, whereby an alloy of sodium and lead it produced which is then reacted upon with nitrogen or a nitrogenous reagent, and in some cases, with an additional reagent, 0. g., carbon or a body containing carbon. In such processes the fixation of nitrogen may be indirectly etfected by the use of one or more metals or metalloids intentionally added to the lead sodium, tin sodium, and other alloy employed, which act as carriers or reactive metals 'by initially but only temporarily fixing the nitrogen as a nitrid, or by firstlproducing a carbid which in turn combines with the nitrogen. The sodium dis places the. reactive metal after or simultaneously with some of the above reactions, to form sodium-nitrogen compounds, 6. 9., sodium cyanid. In bringing about the synthesis of sodium cyanid in this manner, the reactive metal combines directly with carbon, even when sodium is present in the alloy, to form a carbid, and may likewise combine with nitrogen to form a nitrid, but these reactions are only intermediate and transitory, because the reaction proceeds further, in the presence of all the necessary ele ments and under the conditions 0 the process, to efi ectthe synthesis of sodium cyanid.

The intermediate carbid may react with nitrogen: the intermediate nitrid may react with carbon: the nitrid and carbid may react together: and, finally, the alkali metal present in-the alloy displaces and liberates the reactive metal at some point in the synthetic process, while in the form of either nitrid, carbid, cyanamid or cyanid of the reactive metal, principally the latter, and the final result is alkalhmctal cyanid. The reactive metal again becomes available, and is thus used over and over again.

The final result is much the same whether we start with certain previouslyprepared metallic nitrids or carbids and react thereon with commercially pure sodium or potassium and the other element necessary to produce alkali-metal cyanid, to

wit, carbon or nitrogen in reactive form, or i start with a reactive metal free or alloyed with sodium or potassium, or alloyed with a mixture of metals containing sodium or potassium, which reactive metal? will produce a nitrid or carbid under the conditions of operation, and which will, after eflecting the synthesis of cyanid, be liberated by the alkali metal and thusbecome available for re-use.

Some nitrid-forming metals, and nitrids and carbids thereof, will not serve to combine nitrogen, carbon and sodium to form sodium cyanid. Such ametal is magnesium, for instance. Magnesium will decompose sodium cyanid when heated therewith into magnesium nit-rid and sodium carbid, or sodium and carbon. In other words, the nitrid of magnesium is too stronga compound. Any othermetal which will similarly, or in any way decompose sodium or potassium cyanid under the conditions of this process, will not serve the purpose of intermediary in this process. NaCN, a body containing carbon, may be temporarily reduced by Ba, Li, etc., to Na- C N as a step, but afterward, when free carbon is added, is reconverted to cyanid.

The number of metals and metalloids capable of combining directly with carbon or nitrogen when heated therewith, under suitable conditions, is considerable: they are herein referred to as reactive metals The reactive metals are generally obtained from salts or oxids which are retractory or diiiicult to reduce by ordinary metah lurgical processes. They are tten diiiicult to handle, and special care mart generally be taken to prevent abnormal oxidation. and

active metals. These metals, and also the alkali metals, sodium and potassium may be made by'any known methods, and some electrolyticv process for producing the alloy. Such solvent metals should preferably have melting points below 00 0., and boiling of them may be utilized in the process without being-alloyedwitlr another metal, that is, in astute of-substantial purity,-but in general I refer to manufactureand utilize.

them in .t e formyof' alloys with relatively inert,'heavy, solvent metals, such as tin, lead, antimony, zinc, aluminum 'or'bismuth, which maybe used as the cathode in an points above 800 C. By thus combining or mixing reactive metals or alkali metals, with solvent metal they are more easily manufactured, handle?! and reacted upon. The desirable percentage of reactive metal or metals resent in such alloys is determined by: 1) economy and safety in manufacturing alloys containing relatively small or large percentages of the refracto metal; (2) relative ease with which suc alloys may be handled andreacted upon; (3) relative' 'etliciency in combining with either nitrQ- n-orcarbon, or both; (4) relative fusiility 'and fluidity at moderate tempera-' turea The 'percentage. of alkali metal present in Ialloys to be used in the process is to be determined by considerations (1) and (2) as above. By' roperlyproport oning the constituent meta which will be thinly fluid at a moderate temperature, and th1s1is an important fea ture of the process. I

The reaction between nitrogen or carbon and some of the "reaoifve metals will take lace at temperatures ar belpw the r ge indicated above, so that it is not neces ary in all cases to heat the metals or alloys to such an extent. f

Metallic lithium will, if its surface be kept'brighm absorb nitrogen at the ordinary temperah'lre, but the abso 'tion is much more rapid and complete if t e metal is heated. r m,-

In carrying out the manufacture of alkalimetal cyanids and of the intermediate reactive metal cyanids, cyanamids, nitrids, carbids, etc, the general type of apparatus described in my specified patents may be employed, although it may be modified in of the alloys, or mixture,

-number of separately-heated reaction-chambers, compartments, retorts or vessels, connected thereto'by valved pipes, into which the alloy may be periodically or continu ously introduced and there reacted u on,

under pressure, if desired, and from w ich the partially de leted or impoverished metal may be perio ically or continuously returnedto the electrolytic cells to be again enriched with reactive metal, alkali metal, or both. The reaction-chambers may be heated internally or externally, by the combustion of fuel or by electricity, and the temperature may be higher or lower than that of the electrolyte. The general range of temperature would be that known as. a red heat, although this may vary from about 600 to 1100 (1, which range I designate in this specification as a 'moderate temperature. Alloys of tin or lead with sodium and other metals may be continuouslyor intermittently produced electrolytically in this apparatus up, to 25% or more of sodium, and up to 15% or more of reactive metal, or vice verse, that is to say, less of the former and more of the latter, whichare suitable for the purposes of this process. Appropriate electrolytes for the readil suggest themselves to one amiliar. with t e art. v i

The mixed chloride and fluorids of alkali, alkalineeearth and other metals may he employed as an electrolyte, and when the voltage and current density are sufiiciently high, each salt in the mixed electrolyte will be urpose regularly decomposed, the metalsthereofbebon in one of their reactive forms over a considerable range of temperature to form nitridsmncarbids, and with both nitrogen and carbon to form cyanids, a. g.","barium cyanid, lithium cyanid, calcium cyanid, etc.

If the alkali metal, sodium orpotassium,

is also present in the alloy, theabove-men tioned-cyanids will be decomposed with l-ib- "erat-ion of the base metal, e. 9., barium,

. muth, aluminum, and mixtures thereof, and A .will readily combine with nitrogen or carand the metalloids boron, silicon and phosphorus, readily alloy or mix or (OIIIbLIL with tin, and also with antimony, zinc, aluminum,

bismuth, and mixtures thereof, in which lead of a good red heat, to form nitrids or carbids. The alkali metals,-sodium and potassium, may be present in these alloys.

The nitrogen is preferably injected into the molten mass in such manner that the progress upward through the alloy impeded by friction against solid surfaces such as refractory brick, stone-ware, metals, or, if cyanid is being made, charcoal or coke in lumps so disposed that the gas in rising through the same will be held in contact with the other reagents as long as is necessary to effect the combination.

The nitrogen is preferably obtained from the a'ir, although ammonia or other nitrogenous gas "may .be used for special purposes. If ammonia is employed in whole or in part, the temperature of the alloy may be held considerably below that required for nitrogen. flThe nitrogen gas may be dry and pure, or diluted and mixed with one or more other gases, such as ammonia, hydrogen, carbon monoxid, etc., and may be heated or superheated previous to its introduction into the hot mass. Uncombined nitrogen, alone or carrying other gases or solids mixed therewith or in suspension, escaping from one reaction-chamber, may be reintroduced into the same chamber, or carried to a condenser or scrubber to catch the gas, fumes, or solid material in suspension. \Vater, acids, alkali, iron salts, etc., may be employed in the condenser or scrubber to dissolve or catch such residual gas orfumes. Several such scrubbers may be used in series, to dissolve or catch different constituents of the gas or fume.

In the patents above referred to, the nitrogen was injected into the molten metal under some pressure, due to the column of metal which had to be overcome. I have found that it is desirable in reacting on some of the alloys with nitrogen or carbon, or both. to eniploy a' greater pressure than thatinvolved in the above, and I may employ' pressure as high as 75 pounds per square inch.

The steel or othermetal pipes for inject ing nitrogen into some molten alloys must be )ltllttlttl by refractory tubes, sleeves or coating. in some cases carbon or graphitize'l carbon tubes are necessary, which w ar away slowly and gradually and are then renewed. "luhes for use in the process nniy .iiso be made of porcelain, china, fused (unlit/7. or other refractory material.

The carbonaceous reagent maybe in the form of coke, charcoal, lampblack, soot, pitch, tar, gas-carbon, acetylene, hydrocarbon oils, crude petroleum, or any suitable body containin carbon.

\Vhen granuIar charcoal or coke is employed, the carbid is generally formed as a mere superficial layer on the surface of the carboiubut when the reagent is employed in the form of a gas, hydrocarbon oil, or lampblack. the resulting carbid generally a finely-divided apparently amorphous product, which rises to the surface of the alloy and mixes with the cyanid. The carbids thus produced with few exceptions are'not fused, and they are not produced in lumps or masses easily removable.

The carbid produced by this process is. as a rule, of-much greater purity than the or dinary commercial carbid.

If nitrogen alone (without carbon) is in troduced into the alloy, the product will be a nitrid of the reactive metal, and if carbon alone (without nitrogen), is introduced, the product will be a carbid of the reactive metal.

The primary intention is to react with nitrogen upon the carbid, in situ, while still hot and while in contact with or submerged in the moving or circulating alloy. The molten alloy may, however. be withdrawn fron'rthe chamber containing the carbidcoated charcoal or coke, or carbid-containing mass, which may then be reacted upon under pressure with nitrogen or other reagent, or the carbid may be ,otherwise treated, after which the molten metal. containing one or more alkaline metals, or both. may be again run into the chamber.

A different type of apparatus from that referred to in the foregoing may be employed in which to carry out the process. for instance :-'lhe r active metal, alkali metal, or both, as well as alloys thereof. may be reacted upon in molten condition by nitrogen, carbon, nitrid, arbid. cyanamid, cyanid. etc., under pressure. in heavy closed, revolving retorts or cylindersprovided on the inside with shelves, pockets. ledges or arms which will lift a portion of the metal or alloy as the cylinder revolves and afterward spill or discharge the same in such a manner that the clean metal surfaces will be continually or intermittently exposed to the reagent.

The product formed in my process by the interaction of the reactive metal, and both carbon and nitrogen, without the alkali metal, is a cyanid of the reactive metal. if such reactive metal cyanid is stable at the temperature of the Operation. More or less cyanamid may also be formed in some cases. These intermediate cyanids may be reacted upon and utilized in sitn. if desired, in several different ways for dif ferent purposes. The cyanid or cyanamid of the reactive metal may be treated subsequent. to its formation at a moderate temperature with an alkali metal or an alloy containing it, \vhereb alkali metal cyanid is formed and the original metal of the cal-bid is generally set free and becomes a part, of the surrounding body of molten metal at the moment of its liberation, but I prefer to react immediately and simultaneously or practically so. on the carbld of the reactive metal with nitrogen and with the alkali metal, in order to produce at once alkali 'metal cyanid, c. sodium cyanid, in molten condition, which will rise through the molten reactive metal, if in the form of an alloy with a heavy metal. and may be continuously, or intermittently, withdrawn from the reaction chamber.

It will, of course, be understoodthat it is not necessary to first or separately make the carbid referred to in the preceding paragraph. This carbid may be formed practically at the same in unent that it is reacted upon with nitrogen or both nitrogen and sodium. And finally it will be understood that both nitridand earbid in varyin proportions may be initially formed an further reacted upon at the moment of their production or at any time afterward.

In making alkali metal cyanid by this process, it is advisable in efl'ecting the reactions with alkali metal, reactive metal, or both, to employ an excess thereof, and this is also true of the carbonaceous reagent.

The alloys containing certain'o'f the re active metals. such as calcium, barium, strontium, lithium, or either of the alkali metals. sodium or potassium, or mixtures thereof. will absorb and combine with hydrogen if that gas is substituted for nitrogen in the process hereunder and the tem- 'perature is i'naintaincd generally lower than a bed heat, with the formation of the hydrids of calcium, barium,,etc; These hydrids. and others, may thus be produced in the.identical apparatus and by the same process described herein, and in U. S. Patent No. 914,214, for the manufacture of nitride, by employing hydrogen as the reagent instead of nitrogen.

Suitable apparatus for carrying out the ocess is shown in the. accompanying druw-.

mg, in which.-

Figure 1 is a vertical longitudinal section of one complete apparatus; and Figs. 2 and 3 are a vertical axial section and a transverse vertical section, respectively, of a. modified reactionchamber.

The'apparatus illustrated in Fig. 1 com prises an electrolytic cell 1 of the type illustrated in my specified patents, having a cathode of molten metal, and 2, 3, are-delivery pipes fbr the alloy, with an intermediate centrifugal pump 4, for delivering alloy to the reaction-chamber 5. A pipe 6 serves to return the depleted cathode metal to the cell. A body 7 of the alloy is Shown in the reaction-vessel, and, superincumbent thereupon, a body 8 of the molten product, shown as containing ulverulent carbon. A pipe 9 serves for the introduction of mineral oil, if used to supply carbon, and a pipe 10 for the introduction of hydrogen. An electrode 11, depending into the molten cyanid or other product, may be used to pass an electrolytic current thcrethrough to the metal within the vessel, to supply further heat. valved pipe 12 serves to Withdraw the molten product. The pipes 3 and (i-may be closed l a cook or cocks 13, if de sired. to enable superatmospheric pressureto be maintained in the reaetionchan'iber.

The modified reaction-chamber 5' shown in Figs. '2 and 3 consists of a revoluble horizontal drum 14, having at its ends hollow trunnionslfi supported on rollers 16. The

trunnions are closed at their ends by caps 17 containing gas-pipes 18. A screw-plug 19 in the side of the vessel serves for the introduction of desired ingredients, and shelves 20. having marginal flanges 21, projecting from the inside of the vessel, serve to lift and agitate the contents. The vessel is shown surrounded by a brickwork 22, having an opening;' 23 registering with the. screw-plug 1S) and closed by a cover 24.

I claim:

1. The process of producing alkali metal cyanogen compounds. which consists in subjecting ametal capable when heated of combining directly withcarbon or nitrogen, to

the action of heat andfa carbonaceous reagent for the purpose of producing a carbid, reacting on said carbid with a nitrogenous'reagent in the presence of an alkali metal thereby producing an alkali metal cyanogen compound, and liberating the firstmentioned metal.

2. The process of producing alkali meta: cyanogen compounds, which consists in so? jecting a metal capable when heated of com bining directly with carbon or nitrogen, to the action of heat and a carbonaceous'reagent for the purpose of producing a carhid,

reacting on said earbid with a ntro nous a base, the intermediate compound being then decomposed. by the alkali metal with production of an alkali metal cyanogen compound and liberation of the reactive metal which again becomeslavailable for reuse.

4. The cyclic process of producing alkali metal cyanogen compounds, which consists in subjecting a reactive metal to the action of heat and a carbonaceous reagent to produce a carbid of the reactive metal, reacting on said carbid with a nitrogenous reagent to produce an intermediate cyanogen compound having the reactive metal as a base, and finally reacting on said compound with an alkali metal, whereby an alkali metal cyanogen compound is formed and the reactive metal again becomes available for reuse.

The process of producing alkali metal cyanogen compounds, which consists in sub jeeting an alloy containing a metal capable when heated (if-combining directly with carbon or nitrogen, to the action of heat and a carbonaceous reagent for the purpose of producing a carbid. and reacting on the earbid with a nitrogenous reagent in the presence of an alkali metal thereby producing an alkali metal cyanogen compound and liberating the tirst mentioned metal.

t). The process of producing alkali metal cyan gen compounds, which consists in subjecting a metal capable when heated of combining directly with carbon or nitrogen t?) the action of heat and a carbonaceous reagent tor the purpose of producing a carbid, reacting on said carbid with a nitrogenous reagent to produc an intermediate nitrogen compound, and reacting on said intermediate compound with an alkali metal alloy, thereby producing an alkali metal cyanogen compound and liberating the first mentioned metal.

7. The cyclic process of producing alkali metal cyanogen compounds, which consists in sul'ijecting a reactive metal to the action of heat and a carbonaceous reagent to produce a finely dividcd carbid of the reactive metal reacting on said carbid with a nitrogenous reagent to produce an intermediate cyanogen compound having the reactive metal a base, finally reacting on said compound with an alkali metal alloy, whereby an alkali metal cyanogen compound is formed and the reactive metal" again becomes available for reuse, supplying fresh alkali metal to the alloy and repeating the process as described.

8. The cyclic process of producing alkali metal cyanogen compounds, which consists in subjecting barium to the action of heat and a carbonaceous reagent to produce finely divided barium carbid. reacting on said carbid with a nitrogenous reagent to produce a ey anogcn compound of barium, reacting on said barium compound with an alkali metal alloy, whereby an alkali metal compound is formed and the barium again becomes available tor reuse, supplying fresh alkali metal to the alloy and repeating the process as described.

9. The process of producing nitrogen compounds, which consists in reacting with nitrogenous and carbonaceous reagents on an alloy of an inert metal, an alkali metal, and a third element having greater activity toward carbon and nitrogen than said alkali metal.

10. In a process for producing nitrogen compounds, the step which consists in reacting with nitrogen on a mixture of three elements, one of which is an inert diluent and two of which are capable of forming cyanids which are stable at a red heat.

11. The process of producing sodium cyanid, which consists in reacting with nitrogenous and carbonaceous reagents on an alloy of lead, sodium, and barium.

12. The herein described process, which consists in electrolyzing a molten compound containing two metals, alloying the separated metals with a cathode metal, removing the alloy and reacting on the alloyed metals with nitrogenous and carbonaceous reagents, and returning the'residual metal to the cathode.

13. The herein-described process of producing alkali metal cyanogen compounds, which consists in electrolyzing a molten compound containing the alkali metal and another metal having greater activity toward carbon and nitrogen than said alkali metal, alloying the separated metals with a cathode metal, removing the alloy and subjecting it to the action of a nitrogenous gas and a carbonaceous reagent, and returning the residual metal to the cathode.

14. The herein-described process which consists in electrolyzing a molten compound of a metal, alloying; the separated metal with a cathode meta removing the alloy and reacting with nitrogenous and carbonaceous substances on the alloyed metal with production of an intermediate compound, supplying a separate reagent and reacting therewith on the intermediate compound, with production of the desired compound, and returning the residual metal to the cathode.

15. The process of producing cyanogen compounds, which consists in electrolyzing a molten compound of a reactive metal, alloying the separated metal with a cathode metal, removing the alloy and reacting on the alloyed metal with nitrogenous and carbonaceous reagents, and returning the residualmetal to the cathode.

16. The process of producing alkali metal cyanogen compounds, which consists in electrolyzmg a molten compound containing the alkali metal and a reactive metal, alloy- In testimony whereof, I afiix my signature ing the se aratmli1 glkali land reactifie in presence of two witnesses. metals wit a cat 0 e meta removingt e n alloy and reacting on the alloyed metals CHARLES ACKER' with a nitrogenous gas and a carbonaceous Witnesses:

reagent, and returning the residual metal SUSIE E. SAMPSON,

to the cathode. ETHEL R. HARRISON. 

